(a) This chapter applies to medical billing and processing for health care services provided to injured employees subject to a workers' compensation health care network established under Insurance Code Chapter 1305, and to injured employees not subject to such networks, with the following exceptions pertaining only to health care services provided to an injured employee subject to a workers' compensation health care network established under Chapter 1305:(1) Subchapter D of this chapter (relating to Dispute of Medical Bills);(2) §133.210(f) of this chapter (relating to Medical Documentation); and(3) §133.240(b) and (i) of this chapter (relating to Medical Payments and Denials).(b) This chapter applies to all health care provided on or after May 2, 2006. For health care provided prior to May 2, 2006, medical billing and processing shall be in accordance with the rules in effect at the time the health care was provided.